Hoisting mechanism



Dec. 20, 1932- J. R. MCGIFFERT ET AL HOI STING MECHANISM Filed Nov.13. 1929 2 Sheets-Sheet INVENTOR John R.772-G1ffri 1:4

02a. L. 75er'Z2 A TTORNEY5 Dec. 20, 1932. .1. R. MCGIFFERT ET AL HOI STING MECHANI SM 2 Sheets-Sheet Filed Nov. 15

INVENTORS I ZJ7111 2.772 62 fl a-2?,

02a of; EKIZIf ATTORN Y6.

Patented Dec 20, 1932 UNITED- STATES PATENT-f FF CE JOHN R. rrcerrrnnr AND oLA BERRY, or DULUTH, MIHNESOTA; nssre vons TO CLYDE men wonxs, or DULUTH, MnvNnsorA, A Connorrron or MAINE HoIs'r rNG MnoIrANIsin Application filed November 13, 1929. Serial No 406,803.

This invention, as indicated, relates to hoisting mechanism and has particular reference to a mechanism whereby hoisting mechanism of the'common type is provided with a safety means for the prevention of the accidental dropping of the hoisting load.

Hoisting mechanisms as commonly employed, for example in hoisting building material from the ground level to the upper levels'of a building in the course of construction,

are provided with no means other thanthe manual control of the operator for preventing the accidental failing of the suspended load, whether sueh'load be an elevator carriage or a heavy structural steel member; In

the construction of hoisting mechanism ofthe' type commonly employed the winding spool upon which the hoisting cable is wound is provided with a brake drum on which is *iounted thecommon type of brake band.-

This brake is actuated and controlled by a foot lever-or hand lever, whichis manipula-ted by" the operator of the hoist. fAfter the driving means has been disconnected from the winding spool the load is held in elevated position by the application OfthB above mentioned brake and the load is so held suspended only so long as the operator continues the application of the brake. The brake by which'the load or elevator carriage is held in elevated'position is usually the same brake by which-the descentof the-carriage or material is regulated.

lVith the confusion necessarily incident to building construction and the many distractions which, arepresent in the neighborhood of the hoisting mechanism operator there are 7 numerous possibilities for such'op'eratorbecoming confused and releasing 1 the brake with the resulting precipitationof' the sus-' pended load and injury to persons in the viein'ity where the load is dropped. A further source ofda-nger is the carelessness by which the hoisting mechanism is controlled by certain types of operators.

It is a purpose of our" invention to pro-- vide a safety means for hoisting mechanism whereby any accidental dropping of the sus: pended load is impossible. It .is a further object of our invention .to provide a; safety device forhoisting mechanism which shall be operable at all-times and can in no waybe impaired by'anycareless or unpremeditated act'of the operator. .Other objects of our in- 'vention will be apparent as the description 1 proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claim; the annexed drawings 7 and the. following deserip tion setting forth in detail certain mechanism- 1 Fig; l is a plan view of a hoisting mechanism' embodying the principles of our inventlon; Fig. 2 1s a slde elevation of the mechan sm shown 1n Fig. 1; F 1g; 3 is 'a broken fragmentary side elevation of the control lever; and Fig. & "is apart section part eleation ofthe fluid valve shown in eferring more specifically tothe-draW- ings, and more especiallyto Fig; 1, the hoisting mechanism here shown for-the purposes of illustration is of the common type and has side base frame members I and 2 and end base frame members 3 and 4, Intermediate-1y of the ends of the members 1 and" 2 sills 5 and -5 are provided for supporting the hoisting mechanism as wellas materially stiffening the-base frame upon which such mechanism is mounted- The hoist here shown is ofthe common type embodying windingf spools 6 and 7'which have COELXlilllY-HIOUHtGd therewith'drivingwheels 8 and 9 which are driven 'bytheintermeshing pinion 10 receive ing its rotation from a' source of power, not shown. The driving communication between the winding spools '6 and 7 and the driving wheels 8 and -9, respectively, is effected by means of thecontrol levers'll and 12 which are rigidly mountedon thrust screws 13 and 14, which screws pass through thrust nuts 15'and 16 by which the spools 6 and 7 upon rotation of thejlevers l1 and 12, arethrust into frictional engagement with the beveled.

portions 17 and 18 rigidly united with the driving wheels 8 and 9, respectively. The spools 6 and 7 have one of their terminal portions formed into brake drums 19 and 20,

upon which are operably mounted the brake bands 21 and 22. The brake bands 21 and 22 are commonly termed the service brakes and are the means by which the descent of the elevated load held by the cables wound on the spools 6and 7 is controlled. One end 23 of the service brake 21 is mounted on the pin 24, which is rigidly secured in the side of the base sill 5. brake 21 is pivotally mounted on the pin 26 which is rigidly and eccentrically connected with the shaft 27'. The shaft 27 is suitably journaled in the base frame member 1 and the bearing 28 which is rigidly mounted on the sill 5 by means of the brace 29. Rigidly 20' mounted on the shaft 27 is a foot lever 30,

which has a foot pad 31 mounted on the end.

' secured thereto a foot pad 39 adapted to re-* ceive the foot of the operator.

The members 30 and 38 when depressed by the foot of the operator rotate the shafts 27 and 35, which shafts actuate and'tighten the service brakes 21 and 22, respectively. The

service brakes 21 and 22 have projecting lugs 40 and 41, respectively, formed intermediate ly of their ends, which lugs are adapted to receive the adjusting bolts 42 and 43 which are employed, along'with their associated nuts, to effect the proper adjustment of the brake bands 21 and 22 on the drums 19 and 20.

On the terminal portions of the spools 6 and 7, oppositely disposed from the brake drums 19 and 20, are like brake drums 45 and 46, wht'chhave mounted thereon the safety brakes 47 and 48. The end 49 of the safety brake band 47 is pivotally mounted on the member 50 by means of the pin 51, and the other end 52 of the brake band 47 is also pivotally mounted on themember 50 by means of the pin 53. The member 50 is rigidly mounted on the oscillatable shafto54' and the axis of the pin 53, to which the end 52 is mounted, is nearer the axis of rotation of The other end 25 of the service rigidly secured to the side base frame member 2 by means of the supporting members 59 and has its interior adapted to receive the piston 60 which is terminally mounted on the piston rod 56. The cylinder 58 has a closure member 61 secured to one end thereof and through which passes the piston rod 56. Coaxially mounted on-the piston rod 56 is a compression spring 62, which at one end rests against the closure member 61 and at" the other against the piston 60 and normally maintains the piston toward the left end of 48 is secured to the member 64. Rigidly mounted on the shaft 67 is a crank arm 69, towhich is pivotally secured a piston rod 7 0 by means of'the pin 71. rigidlymounted on the sidebase frame member 2by means of the supporting legs 73, the

, interior of such cylinder 72 being adapted to receive the piston 74. The cylinder 72 has a closure member 75 secured thereto at one end, through which passes the piston rod 70, andthe piston rod is in turn connected to the piston 74.. Coaxially mounted on the piston rod 70 is a compression spring 76 which bears against the closure member and the A cylinder 72 is piston 74, and normally maintains the piston 74 to the right in the cylinder 72, as shown in Fig." 2. 6 1 I Coaxially mounted with the shaft 77, on whichxthe driving pinion 10 is mounted, is a driving means 7 8 which is in driving com munication with the driven'means 79 by the resilient means 80, as shown in Fig. 2. The driven means 79 operates the pump 81, which is shown in Fig. 2 to be of the common type I of air compressor. The compression pump 81 has a conduit 82 in communication with the tank 83. The tank 83 has a conduit 84 leading therefrom which branches into conduitsi85 and 86 leading to the safety brake actuating mechanism.

The control levers 11 and 12, shown in enlarged scale in Fig. 3, have their terminal portionsformed into a handle 87, and mounted on the lower end of such levers is a fluid valve 88, shown in enlarged section in Fig.

4. The fluid valve 88 is actuated by means of the rod 89 which is pivotally mounted on the pin 90 carried by the terminal portion of the lever 91, which is pivotally supported at 92 on the side of thelevers 11 and 12, and which has a portion 93 extending therefrom adjacent the handle 87. I

The fluid valve 88 has its central portion the lower compartment 96.

formed with compartments 94, 95 and 96, the terminal compartments 94 and 96 being closed by the end members 97 and 98. The fluid conduit means 85 or 86 is connected to The compartments 94 and 95 are separated by a Web 98, which has its central portion formed into a bearing surface adapted to receive the plunger 99. The compartments 95 and 96 are separated by a web 100 which has its central portion formed into a bearing surface adapted to receive the plunger 101. The closure member 97 is centrally adapted to laterally support theterminal portionv of the rod 89. The plunger 99 has its terminal portion 102 formed into a laterally extending circumferential flange adapted to receive the compression spring 103 positioned between the flange 102 and the web 98. Intermediately the flange 102 and the portion of the plunger 99 which passes through the web 98, the plunger 99 has a valve seat 104 formed thereon which 1 is adapted to contact with the correspondingly beveled surface 105, formed on the upper side of the web 98 surrounding the aperture receiving the plunger 99. The portion of the plunger 99 which passes through the web 98 has a plurality-of longitudinal grooves 106 formed therein.

The web 100 separating the compartments 95 and 96 is centrally adapted to receive the plunger 101, which plunger 101 has an annular valve seat 107 formed thereon and adapted to engage the correspondingly beveled seat 108 of the web 100. The plunger 101 has a closure member 98. The plunger 101 has a plurality of longitudinally extending grooves 112 formed in that portion thereof which passes through the web 100. In communication with the compartment 94 is an exhaust conduit 113, and in communication with the compartment 95 is a conduit 114, which is likewise in communication with the cylinders 58 or 72.

In operation of the hoisting mechanism, the function of the various parts is substantially as follows. The direction of rotation of the spools 6 and 7 during the winding of the cable thereon by which the load is hoisted, is indicated by the arrowson Fig. 2. The operation of the service brake by means of the treadles and 38 is believed to be well enough understood by those acquainted with the art without further explanation. As the spools 6 and 7 rotate in the direction indicated by the arrows on Fig. 2, that is, while the cable is being wound on the spool and the load hoisted, the ends 49 and 63 of the safety brakes will drag on the pivotally supported members 50 and 64, respectively, and thereby release the safety brake and permit a free ro- V tation of the spools 6 and 7. When, however,

therotation of the spools ceases thespringsv 62' and 76, respectively, cause the crank arms and 7 Oto rotate the shafts 54 and 67 and thereby immediately cause an applicationof the safety brake. It will be seen therefore that the safety brake at all times is in normal engagement and any unwinding of the spools 6 and 7 is entirely prevented. In order to release the safety brake the operator must grasp the handle 87 of the operating lever and withjsuch grasping raise the member '93 alongside the handle 87. This movement of. the'member 93 by the handjof the operator causes an opposed movement of the rod 89 connected to the fluid valve 88.

The fluid valve in the position shownin- I Fig. 4 is the position in which such valve is normally maintained, and the fluid'enters the conduit and fills the chamber 96, the valve 107 preventing further passage of the fluid. hen, however, the member 93 has been brought to the position shown in full lines in Fig.3, the lower end of the rod 89 compresses the spring l'03, forcing the plunger 99 down-x wardly through-the web 98 until the annular valve seat 104 comes into contact with the beveled face 105, which contacting prevents any fluid from passing from chamber to chamber 94. As the plunger 99 is pushed downwardly by the rod 89 the lower portion of the plunger 99 strikesthe upper end'of the plunger 101' and. forces it downwardly through the web 100, compressing the spring 110 and unseating the valve 107, permitting fluid flow from chamber 96 to chamber 95 and out through the conduit 114.

lVith the member 93 in the position indicated by full lines in Fig.3 it will therefore be seen that the pressure tank 83 is in direct communication with the conduit 114. The efiect of the pressure in the conduit 114, which is delivered to the cylinders, moves the pistons in the cylinders against the compression springs and causes the piston rods 56 and 70 to be moved out of thecylinders 58 and 72. This movement of the piston rods actuates the crank arms 55 and 69 and releases the safety brakes and permits the operator to lower the suspended load.

It will be seen from the foregoing description that the safety device comprising our invention is operable at all times and absolutely prevents the descent of the suspend- 7 ed load until the premeditated act of the operator moves the member 93 from the position shown in dotted lines in Fig. 3 to that shown in full linesin the same figure. Any

unpremeditated act or careless move that the operator may make can in no way affect the operation of the safety brake'and permita falling of the suspended load. It will also be seen that the operation of the safety brake is positive at all times and does not depend upon the pressure in the fluid tank 83 for bringing the safety brakes: into engagement with their associated drums. It is the springs 62 and 76, along with the action of the pivotally supported members 50oand 64:, Which cause the applieationof the safety brake and no failure in the fluid pressure can in any way endanger the operation of the safety device. 7 V

Other modes of applying the principle of our invention may be employed instead of the one explained, change being made as regards the mechanism hereln disclosed, provlded '7 the means stated; by the following claim or the equivalent of, such stated means be employed.

We therefore particularly point out and disi tinetly claim as our invention':

In ahoisting machine having a Winding spool, means for driving said spool, a lever for effecting driving communication between said driving means and said spool, a brake band mounted on said drum, and resilient means for normally engaging said band on said drum, the combination of fluid actuated means for releasing said brake, valve means associated with said lever for control ling the fluid supply to said last-named means, and means for actuating said valves mounted on said handle and positioned so as to be grasped by the operator While manipulating such lever.

Sw'ned b us this 8th da T of November I JOHN R. MOGIFFERT.

OLA L. BERBY. 

